1. Field of the Invention
The present invention generally relates to a temperature protection device. More particularly, the present invention relates to a temperature protection device that is able to more precisely determine an overheated state of a semiconductor device of, for example, a motor control device, to more reliably protect the semiconductor device from overheating.
2. Background Information
Typically, a power-converter temperature protection device can be provided on the cooling fan for the main circuitry of an inverter. For example, as described in Japanese Unexamined Patent Application No. H-121595, a power-converter temperature protection device can include a temperature sensor that can detect the temperature of a switching element of an inverter primary circuit and output the detected temperature. Also, the power-converter temperature protection device can include a first temperature protection device that decreases the frequency of a carrier signal below a set frequency in response to a protection operate command when the detected temperature is greater than a first heat temperature. The power-converter temperature protection device can further include a second temperature protection device that decreases the torque limit value below a set value in response to a protection operate command is input when the detected temperature is greater than a second heat temperature that is higher than the first heat temperature.